1. Field of the Invention
The present invention relates generally to wireless communication systems utilizing time division multiple access (TDMA) techniques, and more particularly to the assignment of time slots in a dynamic fashion in such communication systems.
2. Description of the Related Art
In cellular telephone systems, methods for assigning time slots in a dynamic fashion are known. These methods exist, for example, in Global Systems for Mobile (GSM) communication systems. Such systems define multiple time slots, each of which may be uniquely assigned to a mobile unit for communication. Here, one of the time slots that is not already in use is selected for temporary use in a communication between base and mobile units, another one of the time slots is selected subsequently, and so on. Other systems, such as xe2x80x9cfixed wireless systems,xe2x80x9d however, are inherently different from cellular telephone systems. What is needed are alternative methods of dynamically assigning time slots which are suitable to other systems, such as fixed wireless systems.
Methods and apparatus for dynamically assigning time slots in a wireless communication system are described. One method includes the initial steps of receiving, at a base unit, a first message from a remote transceiver unit; and processing the first message and generating a second message in response. The method includes the further steps of, when an Me time slot of a time frame is available, sending, from the base unit to the remote transceiver unit, the second message that is responsive to the first message in the Mth time slot; and receiving, at the base unit from the remote transceiver unit, a third message that is responsive to the second message in the Mth time slot of a following time frame. The method includes the further steps of, when the Mth time slot of the time frame is unavailable, sending, from the base unit to the remote transceiver unit, the second message that is responsive to the first message in an Nth time slot of the time frame, where the Nth time slot follows the Mth time slot in the time frame; and receiving, at the base unit from the remote transceiver unit, the third message that is responsive to the second message in the Nth time slot of the following time frame.
If both the Mth and Nth time slots are unavailable, the base unit may assign other subsequent time slots in the time frame in a similar fashion (e.g., Pth or Qth time slots). The dynamic slot assignment is advantageously applied to a call establishment scheme, where the first message is a channel access request message, the second message is a channel measurement request message, and the third message is a channel measurement data message. The base unit selects a channel for communication based on the channel measurement data and, continuing with the dynamic slot assignment, sends a message having a channel identifier associated with the selected channel and receives an acknowledgement from the remote transceiver unit.